- HanJin
If you live in a peaceful location, you might want to check out how noisy drones are. This article will explain why certain drones are louder than others and will also showcase some of the most silent drones on the market right now.
Table of Contents
How Loud Are Drones?
Drones can be very loud in terms of their noise volume. There is also a correlation between the distance a drone is flown from the observer and the drone’s perceived volume. We need to know how loud a drone can be heard. This unit of volume is called the decibel.
A decibel refers to the intensity of sand. It is also abbreviated as dB. Because sand is very sensitive, the dB scale can be quite large. Normal hearing people can hear everything, from the slightest touch to the skin to the roaring of an airplane’s engine. Logarithmic scales are used to measure decibels. It increases by 10 points for every unit of increase.
Here is a table with different dB levels to help you understand the decibel levels relative to everyday sounds.
Decibel Levels
0 dB, which is the softest sand that the human ear can hear, is almost inaudible. This is similar to a leaf falling onto the ground. Your hearing will be damaged if you are exposed to sand above 140 dB. Long-term exposure to loud noises of 85 dB or more can also cause damage.
As you can see, noises can quickly reach dangerous levels. Your hearing will be protected if you reduce the time spent listening to loud noises. The drones can be heard at levels between 70 and 80 decibels. This is very close to the excessive noise level of 85 dB, and prolonged exposure to these noises will definitely damage your ear. Drones are designed to fly far from you, so it is unlikely that you will be exposed to loud drones for long periods of time.
Why Are Drones So Loud
Drones can be loud because propellers travel quickly through the air and displace large amounts of air rapidly. This creates pressure spikes as the propeller spins, causing a distinctive buzzing noise. A lot of noise is also created by the propeller blades’ rapid motion and the effort of electrical motors.
These are the four main reasons drones make so much noise when they hover and fly:
Rotation frequency of propellers – As we discussed above, propellers that whip through the air fast will generate a higher frequency. You can’t do much about drones that require a high-frequency rotation. This is what keeps the drone in the air. To avoid the “swarming bees” sound, you can opt for a larger drone with a slower rotational speed.
Propeller blades crossing over arms – One of the main reasons drones produce a loud sound is because the propeller blades must pass over the arms that extend beyond the drone’s body. The propeller blades passing over arms create a temporary high-pressure system above the arm, which stops the aircraft from producing pressure. This creates a pressure wave and a sound that is of a very low frequency.
The drone’s size and weight will determine how fast propellers can generate the necessary don’t thrust to allow it to hover. The propellers of a heavier drone will spin more quickly and be louder. For comparison, a helicopter is the loudest heavy drone.
Propellers’ length, pitch, and depth. Larger propellers place more air while spinning. This means that they produce more thrust and require a lower rotational frequency to keep the drone in the air. The pitch of the propeller also affects the sound. It determines how much disturbance the drone causes in the air.
A drone will sound louder if it is flying in quiet surroundings than if it is flying in busy areas. The more ambient noise there is from other people, vehicles, music, or anything else nearby, the less drone noise you’ll hear.
Why Are Some Drones Louder Than Cars?
This question is answered by the frequency of the sounds produced. Deep bass sounds are produced by car engines. The vibrations produced by small drones are higher than those of larger engines. The annoying, high-pitched screeching of the wings is what you are hearing. The same thing happens with some drone models, which is why NASA officially rates them higher in terms of noise pollution than cars.
Where Can You Use Quiet Drones?
A drone can be used in many different ways. However, a loud model can cause disruption in various settings. A quiet drone is better for many different activities.
Surveillance
Drones are used by many companies for surveillance. These devices are used by the police and army to track suspects and groups who could be involved with illegal activities. Private investigators, private research companies, and security firms all use drone surveillance as part of their investigations. Drones are able to be used at high altitudes and still give them a clear view of what’s going on. The drone’s quieter, the better it can provide discreet surveillance.
Fishing
A drone can be a great tool for fishing. They can be used to view the water and spot fish areas. You can also use them as entertainment while waiting for your catch. Fish can scatter, just like other species of wildlife. A quiet drone is the best choice for this activity. Other features such as speed, transmission range, and camera will also be important. You should make sure that the model you are using for fishing is waterproof in case it gets wet or falls too low into the water.
Video and Photography
Everyone who has ever married knows how important it is to capture the perfect images that will help you recall that special day. A drone is becoming increasingly popular for wedding photography. You can take photos at angles and heights that are not possible with a handheld camera. Drones can also be used for other events, such as family reunions or parties. They can be used to take photos of your yard, farm, or home. Drones can also be used for maintenance, as they allow you to take photos of high-risk areas in your home or business without having to risk your life.
How Can I Make My Drone Quieter?
Drones can be kept in the air, so there is no way to stop them from creating noise and displacing air. We are actually talking about excess energy required to move air and create thrust. The volume of a drone can only be reduced in two ways:
- Reduce drone noise when hovering: There are several products that claim to reduce drone noise while hovering. This balances air displacement and absorbs sound waves created by propellers whipping through the air. This approach is not used by many drones, so accessories from third parties are needed to absorb the sound.
- Changing propeller shape and morphology: Because the propellers or motors generate the most noise, there are many manufacturers that can modify the shape and texture of propellers to reduce noise. Although there are mixed reviews about this method, it is quite affordable to buy stealth propellers.
You can modify your drone in a variety of ways to reduce its noise. So, what does a drone sound like with these improvements? Let’s find out
Increase the number of rotors
Each rotor must displace less air in order to keep the drone in the air, so each motor must work slightly less. NASA’s 2015 prototype drone was designed to eliminate drone noises during flight.
NASA’s drone had eight motors, which means each motor could work at slightly different speeds per minute. This results in smaller harmonics being generated than if there were only four propellers and a reduction of the frequency spectrum. Frequency spectrum spreading is a technique that allows for the precise control of many propellers by an electronic control unit. It was almost impossible to hear the drone at 30 m when it was being flown.
Rotors Although the drones have an improved blade design to reduce noise, and older models still use loud electric motors in the main engines. You can change the rotors. Install a motor glider, and adjust the drone’s speed to medium or slow. You can combine this method with motors or propellers to make a quieter drone.
Bigger slower propeller
It comes down to the fact that larger propellers can move more air than smaller propellers. Each motor does not have to produce the same amount of thrust. People have found that a larger propeller reduces the frequency of the noise, which is also less irritating.
Aftermarket propellers can be purchased for almost any drone. This can affect the noise level. The thrust factor for creating vertical lift will be increased by increasing the propeller diameter. Reduced RPM propellers will cause more stress on the motors, which can lead to increased demands on the internal components. This means that you always get a return on your investment when you change the propellers.
Sand the surface
You will often find logos or other information embedded into a drone that is commercially available.
You can remove any molding marks from a drone by simply using 800 or 600 sandpaper. Then, gently rub the surface to correct the shape. The propellers are typically made of reinforced nylon composite plastic. This is difficult to damage. You don’t have to sand down propellers or risk your drone being thrown off balance. Instead, you can simply rub each propeller the same amount of times. You can also rub each propeller for the same time.
Buy low noise propellers
There are many aftermarket low-noise propellers. You can find low noise quick-release propellers at any retailer, such as Amazon. There are a few ways they can work.
- They reduce the number of revolutions per minute
- Stealth propellers have a smooth surface.
Stealth propellers can reduce noise levels by around 3.5 dB and the number of revolutions per hour by approximately 20%. Super-efficient, smooth blades can also have the side effect of allowing for longer flight times and up to 14% more hovering.
This approach has the advantage that you don’t need to adjust your drone settings to achieve optimal performance. You don’t need to make any setting adjustments. You just need to take the old propellers off and replace them with the new stealth propellers. The DJI Mavic Air will adjust everything. You could adjust the gain to get better performance if there was a software upgrade.
Propeller shrouds
You can also buy what is called a shroud. Dotterel, a company that makes noise reduction and safety shrouds for drone propellers, has created one. They dampen the sound of the drone’s air interacting with its body, arms, and other parts.
The safety shroud absorbs noise from the ground and then reflects it up. Because it is made from acoustic materials, certain frequencies are absorbed into the shroud’s core.
Choose the Propeller Design
There are many types of propellers available today that can reduce drone buzz noise. Drone manufacturers started to develop aerodynamic propellers with lower decibel levels through computer simulations. Some propellers have a 50% reduction in sound volume compared to the traditional ones that are used on most drones. Look online for silent propellers to fit your drone.
Science Is Making Drones Quieter
Since drones began flying, people have wondered how to make them quieter. There are many technical and commercial reasons why a drone should be quieter. You might fly over animals or people or even record audio for a movie. Science began to investigate ways in which drone noise levels can be reduced.
TOP 3 Quietest Drones For Sale
DJI Mavic Pro Gold
Mavic Pro Platinum has one major exception to other DJI models, and that’s the drone’s quietness. DJI claims that the drone’s noise has been reduced by eight decimal places. Although it may not sound that much, the decibels calculated by DJI show that the noise is approximately 40% lower than before.
This is achieved by changing the propeller design as well as the ESCs controlling the motors. Mavic Pro has a new battery type that will give you 30 minutes of flight time. The drone weighs in at 1.62 pounds (732 g), and the drone flies up to 40 mph without wind. It also has a CMOS sensor.
The drone has a high-quality camera that can produce high-quality images and videos at 24 frames per second (4k x 2160). DJI Mavic Pro Platinum is my recommendation if you are looking for a quieter drone than others.
Parrot Mambo
The Parrot Mambo mini quadcopter has many cool features. Mambo is a super lightweight drone that can fly for up to 9 minutes on a single charge. He also has 550 mAH batteries.
The drone can travel at speeds up to 18 km/h (10 mph) and has a working radius of around 20 meters. This drone is the most affordable on the market. Parrot Mambo is not a loud drone and can be used indoors without interfering with your conversations. We can confidently state that Parrot Mambo is one of the quieter drones available on the market.
DJI Spark
DJI Spark is the smallest and most affordable drone DJI makes. It’s also as reliable as any drone you could ever need. It measures 143x143x55mm and weighs in at 300g. Spark’s design is excellent, and it’s a beautiful drone. You will need your smartphone to control DJI Spark. Once you have plugged it in, you can see a live preview of the drone from the air.
Spark also has a feature called “palm launch” that allows you to control your drone with your hands. The drone can hover for approximately 16 minutes, and it has a 12MP camera. This drone’s quality is unquestionable. It is also very beautiful in design. Although this drone is slightly louder than the Parrot Mambo, it still sounds better than commercial drones with much louder buzzing noises. The LED lights on this drone provide better orientation and visibility while flying.
You can search for more drones here: Best Drone Under 500: Top Brands Review 2023
Conclusion
Drone technology would need to come on in an unimaginable leap if drones were to become completely silent.
Now you have a better idea of drone noise’s effects and how to reduce them. We are glad you found this article useful. It is your responsibility to share this article with anyone who might be in need. If you want a quiet drone that is more oriented toward fun than professional cinematography, then the Parrot Mambo should be a good fit for you. Thank you for reading.
